In many situations, users cannot look at or into cell phone or email messages (text or audio) because they are in a meeting or surrounded by other people who may see text or overhear an audio message. To address this issue, existing approaches include the use of steganography; that is, writing hidden messages in such a way that no one, apart from the sender and intended recipient, suspects the existence of the message. Steganography can be applied to different types of media including text, audio, image and video. However, text steganography presents challenges due to lack of redundancy in text as compared to image or audio, but it also includes smaller memory occupation and simpler communication.
Data compression can be used to encode information in one representation into another representation, with the new representation of data being smaller in size. Existing data compression approaches include Huffman coding, which assigns smaller length code-words to more frequently occurring source symbols and longer length code-words to less frequently occurring source symbols. However, a need exists for masking information based on the sensitivity of the data.